Chemistry. a mechanically separate, homogeneous part of a heterogeneous system:

the solid, liquid, and gaseous phases of a system.

8.

Physics. a particular stage or point of advancement in a cycle; the fractional part of the period through which the time has advanced, measured from some arbitrary origin often expressed as an angle (phase angle) the entire period being taken as 360°.

phase

/feɪz/

noun

1.

any distinct or characteristic period or stage in a sequence of events or chain of development: there were two phases to the resolution, his immaturity was a passing phase

2.

(astronomy) one of the recurring shapes of the portion of the moon or an inferior planet illuminated by the sun: the new moon, first quarter, full moon, and last quarter are the four principal phases of the moon

3.

(physics)

the fraction of a cycle of a periodic quantity that has been completed at a specific reference time, expressed as an angle

(as modifier): a phase shift

4.

(physics) a particular stage in a periodic process or phenomenon

5.

in phase, (of two waveforms) reaching corresponding phases at the same time

6.

out of phase, (of two waveforms) not in phase

7.

(chem) a distinct state of matter characterized by homogeneous composition and properties and the possession of a clearly defined boundary

8.

(zoology) a variation in the normal form of an animal, esp a colour variation, brought about by seasonal or geographical change

9.

(biology) (usually in combination) a stage in mitosis or meiosis: prophase, metaphase

10.

(electrical engineering) one of the circuits in a system in which there are two or more alternating voltages displaced by equal amounts in phase (sense 5) See also polyphase (sense 1)

11.

(in systemic grammar) the type of correspondence that exists between the predicators in a clause that has two or more predicators; for example connection by to, as in I managed to do it, or -ing, as in we heard him singing

verb (transitive)

12.

(often passive) to execute, arrange, or introduce gradually or in stages: a phased withdrawal

13.

(sometimes foll by with) to cause (a part, process, etc) to function or coincide with (another part, process, etc): he tried to phase the intake and output of the machine, he phased the intake with the output

14.

(mainly US) to arrange (processes, goods, etc) to be supplied or executed when required

Derived Forms

phaseless, adjectivephasic, phaseal, adjective

Word Origin

C19: from New Latin phases, pl of phasis, from Greek: aspect; related to Greek phainein to show

1705, "phase of the moon," back-formed as a singular from Modern Latin phases, plural of phasis, from Greek phasis "appearance" (of a star), "phase" (of the moon), from stem of phainein "to show, to make appear" (see phantasm). Latin singular phasis was used in English from 1660. Non-lunar application is first attested 1841. Meaning "temporary difficult period" (especially of adolescents) is attested from 1913.

Any of the forms, recurring in cycles, in which the Moon or a planet appears in the sky.

One of a set of possible homogenous, discrete states of a physical system. States of matter such as solid and liquid are examples of phases, as are different crystal lattice structures in metals such as iron. See also phase transition, state of matter.

A measure of how far some cyclic behavior, such as wave motion, has proceeded through its cycle, measured in degrees or radians. At the beginning of the phase, its value is zero; at one quarter of its cycle, its phase is 90 degrees (π/2 radians); halfway through the cycle its value is 180 degrees (π radians), and so on. ◇ The phase angle between two waves is a measure of their difference in phase. Two waves of the same frequency that are perfectly in phase have phase angle zero; if one wave is ahead of the other by a quarter cycle, its phase angle 90 degrees (π/2 radians); waves that are perfectly out of phase have phase angle 180 degrees (π radians), and so on. See more at wave.